Natural gas like all other fossil fuels are a finite commodity and at some point we will run out. Hopefully we will run out after we've found a renewable cost effect replace fuel. Other wise the planets' trees are going to pay hell.
Well let me restate my response. We won’t run out in your lifetime, your children’s lifetimes, their children’s lifetimes, their children’s lifetimes and their children’s lifetimes. We have only used fossil fuels in large quantities for the last 70 years and we have at least another 200 years of supply, and that assumes that electric cars and other alternative energy doesn’t fully develop.